Auditory Network Discoherence in Chronic Tinnitus.

Chronic tinnitus is a common condition with few effective treatments and no cure. Though inconsistent results across MRI studies of tinnitus have slowed mechanistic insight, converging evidence across animal and human studies clearly implicate auditory-system dysfunction. This paper presents a systematic, retrospective assessment of auditory-network function in chronic tinnitus across multiple fMRI datasets. Auditory network nodes were newly defined in this effort, including novel nodes in cerebellum previously linked with somatotopic representations of articulators (lobules VI, VIIIa). Auditory-network connectivity in cerebellum and superior olivary complex was reduced in chronic tinnitus, perhaps explaining the recent success of trigeminal stimulation in improving tinnitus. Auditory-network strength was also reduced, corroborating some recent studies and perhaps reflecting increased spontaneous neuronal activity reported in animal models. Together, these results suggest auditory-network dysconnectivity as a tinnitus biomarker, and that efferent cochlear pathways related to head-centric interoception may play a mechanistic role.